The present invention relates to a sheet-like object identification method and apparatus for inspecting a sheet-like object printed with a plurality of images with a quality inspection unit and identifying whether the sheet-like object is non-defective.
Generally, in a sheet-like object identification method and apparatus of this type, a printed sheet-like object is inspected by a quality inspection unit arranged between a printing unit and a delivery unit, and a non-defective sheet-like object is delivered to a non-defective sheet pile. A defective sheet-like object is delivered to a defective sheet pile arranged in the delivery unit so that it is separated from the non-defective sheet-like object.
According to the conventional sheet-like object identification method described above, among images printed on one sheet-like object, when at one image is defective, even if the remaining images are non-defective, this sheet-like object is regarded as a printing error, and is delivered to the defective sheet pile and discarded. Accordingly, wasted sheet-like objects increase. When expensive sheet-like objects used for, e.g., securities, are wasted, the cost required for printing increases. In a printing press provided with an abnormality detection unit for detecting a supply abnormality such as a register defect of a sheet-like object, even a sheet-like object detected as being abnormal by the abnormality detection unit is regarded as a printing error and discarded although it is not printed at all. Accordingly, in this case as well, the cost required for printing increases.
It is an object of the present invention to provide a sheet-like object identification method and apparatus in which waste of a sheet-like object is eliminated and the cost required for printing is largely reduced.
In order to achieve the above object, according to the present invention, there is provided a sheet-like object identification method comprising the steps of inspecting a printing quality of each image of a sheet-like object printed with a plurality of images, identifying a sheet-like object in a printing state wherein all printed images are defective and a sheet-like object in a printing state wherein printed images mixedly include non-defective and defective images on the basis of inspection results, and imparting different identification information to the sheet-like object in the printing state wherein all the images are defective and the printed sheet-like object in the printing state mixedly including non-defective and defective images on the basis of identification results.